الفهرس 
Types of water in EgyptOnly 14 pages are availabe for public view
 |  | from | 24 |  |  |
| | | from | 24 | | |
Abstract
This study was conducted to detect E. coli O157:H7,
Legionella spp. and H. pylori from groundwater, sea water, River
Nile water, El-Rahawy Drain and hospital wastewater in Egypt
during the study period extend from June, 2010 to July, 2011. E.
coli O157:H7 was detected using culture and multiplex PCR
methods. Legionella spp. and H. pylori were detected using
culture methods. In addition to this, conventional bacterial
indicators (TVBC, TC, FC and FS) were also examined.
● To determine the sensitivity and specificity of multiplex PCR
in detection of E. coli O157:H7, E. coli O157:H7 ATCC 35150
was used. It was found that the detection limit of E. coli O157:H7
by multiplex PCR was 100 CFU/ml after enrichment step.
Furthermore, the multiplex PCR was specific for E. coli
O157:H7, no positive band were detected when E. coli ATCC
25922, Enterobacter cloacae, Klebsiella pneumonia, Proteus
mirabilis, Listeria monocytogenes, Salmonella Typhimurium
ATCC 14028, Pseudomonas aeruginosa, Staphylococcus aureus
and E. coli were used.
● Regarding to the results of groundwater collected from New
Valley Governorate. It was found that, 16 out of 40 groundwater
samples did not comply with Egyptian Standard (2007) for
drinking water due to the high bacterial counts in 16 wells
samples and presence of TC in 3 well samples including one
sample which containing FC.
Summary
- 195 -
● All treated groundwater samples which were collected from 10
wells, Qalyubia Governorate complied with the Egyptian
Standard (2007).
● 15 sea water samples collected from the Mediterranean Sea,
Marsa-Matroha Governorate had relatively high average counts
of TVBC at 37 and 22oC which were 9.2x102 and 1.4x103
CFU/ml, respectively.
● Considering the fifty water samples which were collected from
Rossita Branch along about one Km, the results of bacterial
indicators indicated that, the minimum values were observed
before the mixing point with El- Rahawy Drain. While, the
maximum values were observed at the mixing point with El-
Rahawy Drain. The prevalence of E. coli O157:H7, Legionella
spp. and H. pylori were 32 (64%), 18 (36%) and 33 (66%),
respectively. E. coli O157:H7 was detected in 35 out of 50 (70%)
by multiplex PCR and the presence of six virulence genes (flic,
stx1, stx2, eae, rfbE and hly) was 0 (0%), 10 (20%), 25 (50%), 23
(46%), 15 (30%) and 0 (0%), (with fragment size at 949, 655,
477, 375, 296 and 199 bp), respectively.
● Among the recording 20 water samples collected from 4 sites
distributed along about 5 km of El-Rahway Drain, the averages
counts of TVBC were 9.5x105 and 1.5x106 CFU/ml at 37 and
22oC, respectively. The averages counts of TC, FC and FS were
2.2x105, 1.2x105 and 3.1x105 MPN-index/100ml, respectively.
The prevalence of E. coli O157:H7 and H. pylori was 20 out of
Summary
- 196 -
20 (100%), while the prevalence of Legionella spp. was 16 out of
20 (80%) water samples. E. coli O157:H7 was detected in 20 out
of 20 water samples by multiplex PCR with prevalence
percentage 100%, and the presence of six virulence genes (flic,
stx1, stx2, eae, rfbE and hly) was 1 (5%), 8 (40%), 17 (85%), 19
(95%), 15 (75%) and 1 (5%), respectively.
● 10 separate wastewater samples were collected from El-Kasr
El-Aini hospitals. Average values of TVBC at 37 and 22oC were
6.4x104 and 5.9x104 CFU/ml respectively, while the average
values of TC, FC and FS were 1.5x104, 8.6x103 and 6.2x102
MPN- Index /100ml respectively. In addition to this the average
counts of E. coli O157:H7, Legionella spp. and H. Pylori were
3.6x102, 2.1x103 and 2.2x103 CFU/100ml respectively. E. coli
O157:H7 was positive in 5 out of 10 (50%) using both culture
and multiplex PCR methods, with only three detected virulence
genes (stx2, eae and rfbE). Legionella spp. and H. pylori were
present in 10 (100%), 6 (60%) out of 10 hospital wastewater
samples respectively.
● The O antigen (rfbE) gene in six local E. coli O157:H7 isolates
was chosen for characterization, because it was the most frequent
gene in isolated local E. coli O157, also this gene represent O
antigen gene which synthesis O157 LPS. It was found that,
sequence analyses of positive PCR products of E. coli O157:H7
revealed high homology with two E. coli O157:H7 strains, it
Summary
- 197 -
deposed in database namely (EC 4024) and (09BKT078844) with
Blast identity ranging from 94% to 100%.
● Regarding the statistical analyses. The statistical analyses were
carried out in order to find any possible correlation between
tested pathogenic bacteria and bacterial indicators; It was found
that, there were differences in correlations either by positive or
negative with different variety of significance in different water
tested.
●Regarding to antibiotic sensitivity test of E. coli O157:H7 and
Legionella spp. isolates. It was found that, E. coli O157:H7
isolates were resistant to amoxicillin (100%), clarithomycin
(77%), streptomycin (11%) and tetracycline (7%). While E. coli
O157:H7 ATCC 35150 (strain 1) was resistant to amoxicillin and
clarithomycin. On the other hand, L. pneumophila ATCC 33152
was resistant to cefaxime and clarithromycin. While confirmed
Legionella isolates were resistant to tetracycline (100%),
clarithromycin (100%), ciprofloxacin (80%), amoxicillin (70%),
cefaxime (40%), and streptomycin (30%).
●In survival experiment, E. coli O157:H7 survived in all
sterilized tested water types longer than non sterilized water. It
was found that the E. coli O157:H7 isolated from wastewater
sample had the longest survival time (98 days) in sterilized
wastewater compared to the other strain (reference strain and
isolate of River Nile).
Summary
- 198 -
● In chlorine experiment, in order to reach 99.9% inactivation of
E. coli O157:H7 by chlorine. It was found that, both E. coli
O157:H7 environmental strains form River Nile and wastewater
required higher dose of that than required to inactive the
reference strain E. coli O157:H7 ATCC 35150. Comparing four
log reduction of E. coli O157:H7 ATCC 35150 and L.
pneumophila ATCC 33152 numbers, it was found that L.
pneumophila ATCC 33152 (2.6 mg/l) required higher chlorine
dose than E. coli O157:H7 ATCC 35150 (1.4 mg/l).
Conclusions and Recommendations
● El-Rahawy Drain is the main source of the deterioration of
River Nile (Rossita Branch), thus, it is recommended that El-
Rahawy Drain should be treated before discharging to Rossita
Branch.
● Hospital wastewater should be treated onsite before mixing
with sewerage system.
● The cultivation of E. coli O157:H7 on HiCrome EC O157:H7
selective agar media is considered inexpensive and reliable
detection methods in concentrated water sample; samples with
low counts were easily detected.
● The Multiplex PCR is sensitive, specific, for detection of E.
coli O157:H7; and also, provides a clue for the degree of
virulence; can be used to detect at least one or more of the
Summary
- 199 -
virulence genes which culture, biochemical and serological tests
cannot.
● Combining both culture and PCR methods should be
recommended for the detection of E. coli O157:H7.
● Culture methods for detection of Legionella spp. and H. pylori
were reliable and gave consistent results, but they were time
consuming (4-10 days). It is recommended faster methods to
detect Legionella spp. and H. pylori.
● The absence of consistent, clear and significant correlation
between the presences of bacterial indicators and tested
pathogenic bacteria, it is recommended that monitoring of
bacterial pathogens from time to time a long routine bacterial
indicators examination.
● Due to abuse and misuse of antibiotics, environmental
pathogenic bacteria develop strategies for resistance. Restriction
of antibiotics used should be enforced.
● It is recommended that, test for disinfections control in Egypt,
should be carried out on local pathogenic bacterial isolates
because they showed higher resistance than reference strains.